NONLINEAR PIEZOELECTRIC EFFECT IN CDTE AND CDZNTE

Strained quantum wells (QWs) grown along the polar axis (111) in a zinc-blende semiconductor exhibit a piezoelectric field. This field strongly modifies the energy of excitons confined in QWs. We have extracted, from optical measurements of excitonic transitions, the piezoelectric field value in a large set of QWs: CdTe/CdZnTe, CdTe/CdMnTe, CdZnTe/CdMnTe. By suitably choosing the composition of alloys, we have obtained different values of strains (compressive or extensive) due to the lattice mismatch between QWs and barriers. The non-linear piezoelectric effect appears clearly when plotting the piezoelectric tensor component e14 versus lattice mismatch. For example e14 increases.from 0.07 C/m2 to 0.15 C/M2 when the lattice mismatch varies from - 0.3% to - 1.7%.